The study, however, hasn't convinced a number of scientists, state officials and Aleutian residents who worry about residue from three underground atomic tests on Amchitka more than 30 years ago.

Amchitka is unpopulated but people who live on other islands in the Aleutians fish in Amchitka waters. Steller sea lions have rookeries there, and other marine mammals that are taken by subsistence hunters migrate through area waters.

Critics say the Energy Department's risk analysis and a related study of groundwater movement under the island are based on outdated information collected in the 1960s and early 1970s.

What they want is actual onsite sampling of subsistence foods, and environmental monitoring.

The study was unveiled last week at a series of meetings in Anchorage. The Energy Department will accept comments on the studies until Jan. 31 and then consider revising its work as it begins to develop a long-term management plan.

"This is just an initial step," said Monica Sanchez, the Energy Department's environmental project manager for Amchitka. "We will be back."

The United States set off three nuclear explosions beneath Amchitka between 1965 and 1971. The nuclear residue will remain radioactive for thousands of years. Exposure can cause cancer and other diseases.

Federal scientific models at the time of the tests suggested the radionuclides could begin leaking anywhere from 10 years to thousands of years later.

The new studies attempt to estimate the likelihood that radionuclides could leak into the ocean and the degree of risk posed to humans through consumption of subsistence and commercially caught foods if they do.

The groundwater study was done by Jenny Chapman, a hydrogeologist at the University of Nevada's Desert Research Institute. It concludes that radionuclides could reach the sea floor sometime in the next 1,000 years, or not.

If that happens, strong currents and the enormous volume of water surrounding Amchitka would quickly dilute the radioactive substances to harmless levels, according to the risk assessment by consultant Barney Cornaby of Oak Ridge, Tenn.

He found that the risk of a radionuclide leak from Amchitka causing cancer in a human is one in 10 billion, vastly smaller than the one in 1 million level the federal government considers an acceptable public health risk.

Sanchez and other federal officials said their work will be reviewed by independent teams of scientists, as well as a consortium of university experts that will help the government plan its long-term strategy for Amchitka. State officials and the Aleutian Pribilof association will review them.